1. Field of the Invention
The present invention relates to an improvement of a nozzle cap for a composite container containing a low-viscosity liquid such as humidity-curing type adhesive, for example, .alpha.-cyanoacrylate-based adhesive, solvent-volatile type adhesive, various chemicals, food, and ink.
2. Description of Related Art
Liquid adhesive as a representative of low-viscosity liquid includes different types such as a solvent-volatile type and humidity-curing type, wherein the solvent-volatile type cannot be stored in a plastic tube, and the humidity-curing type also cannot be stored in a humidity-permeative plastic tube. Therefore, the adhesives of these types are conventionally stored in a metallic tube such as an aluminum tube and a lead tube.
However, a metallic tube which has no restoring force, after discharging the adhesive contents, causes a so-called liquid trickle. For example, where the contents such as those of instant adhesive are of a low viscosity, such a phenomenon becomes more apparent. Also, a metallic tube which has no restoring force leaves concavities as it is used, thereby causing its use to become difficult and its appearance to be deformed and become bad. Further, a metallic tube cannot be allowed to stand, so that in order to prevent the contents from flowing out when the tube is laid horizontally in the course of use, a cap must be applied to the tube each time the tube is laid down, thereby becoming troublesome to a user. In addition, where the contents are small in quantity, a problem exists in that a metallic tube is small in size and thus difficult to handle.
In order to solve these problems, as disclosed, for example, in Japanese Examined Utility Model SHO 58-8682 and Japanese Examined Utility Model SHO 62-44914, a fitted mounting of a cylindrical elastic tube or a pipe-shaped plastic on the outer periphery of a metallic tube is proposed.
However, the proposed method is such that the elastic restoring force of the elastic tube or the pipe-shaped plastic allows the metallic tube to be restored and thus a discharged liquid accumulated in its outlet to be sucked, so that the restoring property is not sufficient and thus the sucking force for sucking the discharged liquid is weak. Particularly, a problem exists in that the restoring properties become weak as the tube is used, thereby causing the application purpose to be not sufficiently achieved.
As a result of concentrated research, the present inventor and others have previously invented, as a composite container for a low-viscosity liquid to solve these problems, a composite container which includes an inner container having a body containing contents and a mouth portion for discharging the contents from the body, and an outer sheath container for sheathing the body of the inner container, which allows a pressure medium to be interposed between the inner container and the outer sheath container (Japanese Patent Application HEI 4-198963).
According to the previous invention, the pressure medium causes the restoring force of the outer sheath container to be transmitted to the inner container and thus the restoring properties of the inner container to be sufficiently improved, thereby allowing the liquid trickle to be prevented and the contents to be completely discharged.
However, in the composite container for a low-viscosity liquid in connection with the previous invention, where the container is constructed such that a nozzle is threadably attached to the mouth portion of the inner container and that a cap for closing a discharge port of the nozzle is threadably engaged with the nozzle, if the cap is strongly and threadably tightened, if a discharged liquid having dropped on the outer periphery of the nozzle causes the cap to adhere to the nozzle, or if a discharged liquid having dropped on the outer periphery of the nozzle cures to cause a rise to be formed on the outer peripheral surface of the nozzle, when the cap is removed, the nozzle may be turned together with the cap, thereby causing the nozzle to be threadably disengaged from the mouth portion of the inner container.
Due to this fact, taking the above-mentioned circumstances into consideration, the present inventor and others have previously invented a composite container which prevents its cap from being threadably tightened and more strongly than a predetermined force, and its nozzle from being turned together when the cap is threadably disengaged (Japanese Patent Application HEI 4-348251).
The previous invention is a composite container for a low-viscosity liquid which includes an inner container having a body containing contents and a mouth portion threadably mounted to a nozzle for discharging the contents from the body, an outer sheath container for sheathing the body of the inner container, the nozzle threadably mounted to the above-mentioned mouth portion, and a cap for closing a discharge port of the above-mentioned nozzle, characterized in that in order to achieve the above-mentioned purpose, the outer sheath container is provided with a boss through which a base end of the mouth portion is inserted and which forms ratchet teeth on the outer peripheral surface thereof, while the above-mentioned nozzle is provided with ratchet internal teeth corresponding to said ratchet teeth.
In this previous invention, a cap, for example, as shown in FIGS. 7a and 7b is used, in which case the closure of the nozzle portion is performed by closing a tip of the nozzle by a head plane 2' of a column element 2 projecting inwardly in a head 1 of the cap. With this method, the closure of the nozzle is insufficient in some cases. That is, adhesive or the like adhering to the tip of the nozzle spreads around and cures to form the so-called umbrella- or mushroom-shaped solid material to cause a discharge tip to become thick, whereby the container becomes difficult to use such that precision coating becomes impossible, and thus higher sealing properties are required, in which case the closure cannot be considered to be sufficient. As a concentrated research to solve these problems, the present invention has been completed.